transient vs transiency

transient and transiency both are nouns.

Word	Noun	Adjective	Verb	Adverb
transient	Yes	Yes	No	No
transiency	Yes	No	No	No

transient (noun)	transiency (noun)
(physics) a short-lived oscillation in a system caused by a sudden change of voltage or current or load	an impermanence that suggests the inevitability of ending or dying
one who stays for only a short time

transient (adjective)	transiency (adjective)
of a mental act; causing effects outside the mind
lasting a very short time